1. Field of the Invention
This invention relates to processes of treating metal surfaces with aqueous acidic compositions to increase the resistance to corrosion of the treated metal surface, either as thus treated or after subsequent overcoating with some conventional organic based protective layer. A major object of the invention is to provide a storage stable, preferably single package, treatment that can be substantially free from hexavalent chromium but can protect metals substantially as well as the hexavalent chromium containing treatments of the prior art, or can improve the stability of treatment solutions that do contain hexavalent chromium. This invention also relates to reaction of fluorometallic acids with other metal or metalloid containing materials to produce compositions or intermediates for compositions useful for such treatments.
2. Statement of Related Art
A very wide variety of materials have been taught in the prior art for the general purposes of the present invention, but most of them contain hexavalent chromium or other inorganic oxidizing agents which are environmentally undesirable. Also, many of the prior art treatment compositions include components that are chemically or physically unstable when mixed, so that single package concentrates for such treatment compositions are not practical.